University of Arizona
Biology Project: Cell Cycle and Mitosis Tutorial: Dna Basics
Tutorial on DNA basics that goes along with an online quiz over the material. Use the naviagation buttons at the bottom of the page to go to the quiz over the material.
CK-12 Foundation
Ck 12: Biology: Human Chromosomes and Genes
[Free Registration/Login may be required to access all resource tools.] Covers human autosomes and sex chromosomes.
University of California
Ucmp: Computer Model of Dna
A slight departure from the classic view of DNA showing that the molecule is not exactly a twisted ladder. Good image and explanation to go with it.